1 Reply Latest reply on Sep 8, 2011 11:55 AM by francesco.pietrobelli

How can I get a itemDefinition related to a process variable?

francesco.pietrobelli Aug 10, 2011 11:40 AM

Hi guys,

I would like to build forms for human activities in an automatic and dynamic fashion, but to do this I need to know the data type associated to every dataOutput of the tasks.

My first idea was to retrieve the data type of a process variable inside a WorkItemHandler in the following way:

public void executeWorkItem(WorkItem item, WorkItemManager manager) {
     WorkflowProcessInstance currentProcess = (WorkflowProcessInstance) ksession.getProcessInstance(item.getProcessInstanceId());
     HumanTaskNodeInstance currentNode = (HumanTaskNodeInstance) findNodeInstance(item.getId(), currentProcess);
     Map<String, String> outMappings = ht.getHumanTaskNode().getOutMappings();
     for (String outParameterName : outMappings.keySet()) {
          System.out.println("Type of process variable: "+currentProcess.getVariable(outMappings.get(outParameterName)).getClass());
     }
}


private WorkItemNodeInstance findNodeInstance(long workItemId,NodeInstanceContainer container) {
     for (NodeInstance nodeInstance : container.getNodeInstances()) {
          if (nodeInstance instanceof WorkItemNodeInstance) {
               WorkItemNodeInstance workItemNodeInstance = (WorkItemNodeInstance) nodeInstance;
               if (workItemNodeInstance.getWorkItem().getId() == workItemId) {
                    return workItemNodeInstance;
               }
          }
          if (nodeInstance instanceof NodeInstanceContainer) {
               WorkItemNodeInstance result = findNodeInstance(workItemId,((NodeInstanceContainer) nodeInstance));
               if (result != null) {
                    return result;
               }
          }
     }
     return null;
}

But in many case outMappings.get(outParameterName) returns null because process variable wasn't set before and so and i can't invoke getClass() on it.

Does any one have any suggestion? is possible to do this programmatically via API?

Francesco.

P.S: I'am using jBPM 5.1Final

1. Re: How can I get a itemDefinition related to a process variable?

francesco.pietrobelli Sep 8, 2011 11:55 AM (in response to francesco.pietrobelli)

The only solution i found is parsing the bpmn file in which the process is defined in follwiong way:

org.jbpm.workflow.instance.WorkflowProcessInstance currentProcess=(org.jbpm.workflow.instance.WorkflowProcessInstance)ksession.getProcess(processInstanceId);
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
documentBuilderFactory.setNamespaceAware(true);
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document doc = documentBuilder.parse(((org.jbpm.process.core.Process) currentProcess.getProcess()).getResource().getInputStream());


XPathFactory xFactory = XPathFactory.newInstance();
XPath xPath = xFactory.newXPath();
xPath.setNamespaceContext(new BPMN2Namespaces());

Map<String, String> outMap = currentNode.getHumanTaskNode().getOutMappings();
for (String outParameter : outMap.keySet()) {
     XPathExpression xExpr1 = xPath.compile("//bpmn2:definitions/bpmn2:process/bpmn2:property[@id='"
                                + outMap.get(outParameter)
                                + "']/@itemSubjectRef");
     String itemSubjectRef = xExpr1.evaluate(doc);
     XPathExpression xExpr2 = xPath.compile("//bpmn2:definitions/bpmn2:itemDefinition[@id='"
                                + itemSubjectRef + "']/@structureRef");
     String structureRef = xExpr2.evaluate(doc);

     System.out.println("Type of out parameter named '"+outParameter+"': "+structureRef);
}

But if same one know a way to do that without parsing bpmn file is very appreciated....

Regards,

Francesco